Hey, this line should be indented one more level, or it will never sleep for those two seconds.

Failing package
RPi.GPIO
Error
error: command '/usr/bin/arm-linux-gnueabihf-gcc' failed with exit code 1
Solution
Run before pip install: export CFLAGS=-fcommon
Solution source
Ask Ubuntu

In chapter02, button_gpiozero.py uses debounce time of 0.1 seconds. button_pigpiozero.py uses debounce time of 10000 microseconds. I think the idea of chapter 2 is to execute the same functionality using pigpio and gpiozero, so this difference in debounce time can be confusing for readers.

10000 microseconds == 0.01 seconds != 0.1 seconds

With a default install of mosquitto, it throws the following error unless you modify either the mosquitto.conf file or mostquitto_pyiot.conf file to allow_anonymous true

Connection error: Connection Refused: not authorised.

I ran all the imports and installed requirements.txt - ldr_ads1115_calibrate.py fails with "no module named 'board". I commented out that line, and it also can't find 'busio'

Please advise.